1. American Heritage Dictionary of The English Language (1992), Third Ed. Houghton Miflin Co., Boston and New York
2. Anderson, R. M., S. P. Blythe, S. Gupta and E. Konings (1989), The transmission of the Human Immunodeficiency Virus Type I in the male homosexual community in the United Kingdom: the influence of changes in sexual behavior, Phil. Trans., Roy. Soc. London, B 325: 145?198
3. Bailey, N. T. J. (1975), The Mathematical Theory of Infectious diseases and its applications, Griifin: London
4. Blythe, S. P. and C. Castillo-Chavez (1989), Like-with-like preference and sexual mixing models, Math. Biosci. 96: 221?238
5. Blythe, S. P., C. Castillo-Chavez, J. Palmer and M. Cheng (1991), Towards a unified theory of mixing and pair formation, Math. Biosci., 107: 379?405